1. Field of the Invention
This invention relates to a process and an apparatus for producing a strip joint member by joining strip pieces each made of plural cords coated with rubber.
2. Description of Related Art
As a tire constitutional member is used a strip joint formed by a process wherein a strip embedded with steel cords or the like therein is successively cut into pieces having a given length and then these pieces are joined at their no-cut ends with each other to form a new strip joint.
In an apparatus for producing such a strip joint, the strip is obliquely fed onto a conveyor in a given amount from a position separated by a given distance from the side of the conveyor in a given inclination angle with respect to the conveyor and cut along the side edge of the conveyor, and the thus cut strip piece is moved by a given distance through the conveyor, and then the strip is again fed onto the conveyor in a given amount from the given position in the given inclination angle and overlapped at its edge portion with an edge portion of the preceding strip piece moved by the given distance through the conveyor to join them with each other.
A continuous strip joint formed by successively joining the strip pieces with each other as mentioned above is taken up on a winding roller, and then taken off from the winding roller at subsequent step and cut into a constant length to produce a strip joint having a given length.
Since the continuous strip joint is taken up on the winding roller and again taken off therefrom and cut into the constant length, there are many steps for producing the strip joint of given length and hence the strip piece is easily deformed and it is required to widen an installation space and increase a production cost.
And also, when the continuous strip joint is cut into the constant length, the cutting angle does not coincide with an inclination angle of the cord embedded therein and hence there is caused a fear of exposing the cord therefrom.
Furthermore, even in case of cutting into the constant length, the number of the cords embedded in the strip joint is not necessarily constant among the cut strip joints.
It is, therefore, an object of the invention to provide a process and an apparatus capable of cheaply producing a strip joint of a stable quality, which hardly deforms and does not expose the cords and makes the number of embedded cords constant, at few production steps.
According to a first aspect of the invention, there is the provision of in a process for producing a strip joint by feeding a given amount of a strip of a constant width, which is formed by coating a plurality of cords with rubber, onto a conveyor from a position separated by a given distance at the side of the conveyor in a direction of a given inclination angle, cutting the strip along the conveyor, moving the cut strip piece in a given moving pitch amount through the conveyor, joining a front end portion of a subsequently fed strip piece to a rear end portion of the preceding strip piece, and successively repeating these procedures to produce a continuous strip joint, an improvement wherein the moving pitch amount is adjusted by controlling the movement of the conveyor to produce a strip joint of a required length.
The strip joint of the required length can be produced by adjusting the moving pitch amount in the joining through the repetitive moving of the strip pieces, so that steps of taking up the strip joint on the winding roller and taking off therefrom to cut into a constant length are omitted and hence the number of steps for producing the strip joint of the required length is reduced.
As a result, the possibility of deforming the strip piece is less, and the installation space is made narrow and the reduction of the cost can be attained.
And also, the cutting of the strip joint into the constant length is not conducted, so that the cords embedded therein are not exposed and the number of the embedded cords is always constant, and hence the strip joint of stable quality can be produced.
According to a second aspect of the invention, there is the provision of in a process for producing a strip joint by feeding a given amount of a strip of a constant width, which is formed by coating a plurality of cords with rubber, onto a conveyor from a position separated by a given distance at the side of the conveyor in a direction of a given inclination angle, cutting the strip along the conveyor, moving the cut strip piece in a given moving pitch amount through the conveyor, joining a front end portion of a subsequently fed strip piece to a rear end portion of the preceding strip piece, and successively repeating these procedures to produce a continuous strip joint, an improvement wherein the number of strip pieces to be joined is decided in accordance with a length of the strip joint to be produced based on the constant width of the strip and the given inclination angle of the strip fed to the conveyor, and a moving pitch amount of the strip piece is calculated from the decided number of the strip pieces and the length of the strip joint to be produced, and the strip pieces are repeatedly moved by controlling the movement of the conveyor based on the calculated moving pitch amount to produce a strip joint having the decided number of the strip pieces.
Since the width of the strip piece in a moving direction of the conveyor is constant, when the number of the strip pieces required for joining the strip pieces in the moving direction to produce the strip joint of the required length is decided, the moving pitch amount of the strip piece can be calculated and the strip pieces are repeatedly moved by controlling the movement of the conveyor based on the calculated moving pitch amount, whereby the decided number of the strip pieces can be joined to produce the strip joint of the required length.
Even in this case, the number of steps for producing the strip joint of the required length is reduced, and the possibility of deforming the strip piece is less, and the installation space is made narrow and the reduction of the cost can be attained.
And also, the cutting of the strip joint into the constant length is not conducted, so that the cords embedded therein are not exposed and the number of the embedded cords is always constant, and hence the strip joint of stable quality can be produced.
In a preferable embodiment of the above processes, a margin portion is formed in at least one side edge of the strip.
When the number of the strip pieces to be joined is decided so as to successively dispose the strip pieces on the conveyor in intervals, the subsequent strip piece is overlapped with the preceding strip piece at their margin portions, whereby the joining quality can be improved.
According to a third aspect of the invention, there is the provision of an apparatus for producing a strip joint, comprising a conveyor moving a strip piece, a feeding means for feeding a given amount of a strip onto the conveyor from a position separated by a given distance at the side of the conveyor in a direction of a given inclination angle, a cutting means disposed just before the conveyor for cutting the strip fed from the feeding means into a strip piece, a joining means for joining edge portions of a preceding strip piece and a subsequent strip piece to each other on the conveyor, a computing means for deciding the number of strip pieces to be joined in accordance with a length of a strip joint to be produced and calculating a moving pitch amount in the repetitive movement of the strip piece through the conveyor, and a control means for controlling the movement of the conveyor based on the joining number and moving pitch amount decided by the above computing means.
Thus, the movement of the conveyor is controlled in the calculated moving pitch amount to repeatedly move the strip pieces to join the calculated number of the strip pieces, whereby the strip joint of the required length can be produced.
Even in this case, the number of steps for producing the strip joint of the required length is reduced, and the possibility of deforming the strip piece is less, and the installation space is made narrow and the reduction of the cost can be attained. And also, the cutting of the strip joint into the constant length is not conducted, so that the cords embedded therein are not exposed and the number of the embedded cords is always constant, and hence the strip joint of stable quality can be produced.
In a preferable embodiment of the apparatus, the computing means decides the number of strip pieces to be joined in accordance with a length of a strip joint to be produced based on a constant width of the strip and a given inclination angle of the strip fed onto the conveyor, and calculates a moving pitch amount of the strip piece from the decided number and the length of the strip joint to be produced.
Since the width is constant in a moving direction of the strip piece through the conveyor, the number of the strip pieces required for joining the strip pieces in the moving direction to produce the strip joint of the required length can be decided and the moving pitch amount can be calculated from the decided number of the strip pieces.